Bathtub



FIG. 1 is a perspective view of a bathtub showing my new design;

FIG. b 2 is a top plan view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a side elevational view thereof; and

FIG. 5 is a front elevational view thereof. 

The ornamental design for a bathtub, as shown. 